If you have a system that is running Windows XP, I'll personally drive up there and rescue that poor little thing from becoming so much shrapnel on the wrong end of the shooting range. I'm still using Windows 98, may the gods helps me: but my little piece of shit does tricks it was never meant to do thanks to constant upkeep.
Some folks want an excuse to buy a new PC. If you really would just ENJOY a new PC -- by all means: go for it. If you are also still using Windows 98 and you have the cash to burn -- I'd also say it is high time you got a new PC. Your problem CAN be painlessly repaired, but if you're system is as old as mine is, it's a great idea to start fresh. Us geeks will squeeze every drop of life out of a PC. But for everyday folks who aren't into that or who just don't have the time to tinker, a new system every five years is not completely unreasonable or even unexpected.
But your little Trojan horse issue is NOT a good enough reason by itself to trash your PC.
Since you just installed Ad Aware, the reference file should be up to date. But just in case, open the program again and click the link on the main screen that says "Check For Updates Now." Install any new updates if they are available.
You remembered the other thread in which all those additional programs were mentioned -- very cool. By all means, download and install AVG antivirus if you don't have any virus protection already. It's free. The link, for the convenience of others who don't want to search out the old thread:
http://free.grisoft.com/freeweb.php
You may also want to consider Spy Bot, another good ad-blasting program:
http://www.spy-bot.net/
Both of these can be installed on the same system, of course, and used individually. However, it is wise to NOT run two antivirus programs at the same time. Since you are an admitted PC dummy, I won't bother to get into a boring discussion about settings for virus software. Newbies should accept the defaults and they'll be fine. I personally hate stuff that integrates too deeply into my system, but for some folks it is necessary for virus protection.
Regarding your question about screen names and passwords, etc. As these guys already told you, yes... you can use these same names on any system. You just need to remember them all and the passwords associated with each.
However, a simpler solution exists.
Just copy the contents of C:\Windows\Cookies. There may be thousands of files here -- or just a few hundred. They are extremely small files and it is likely you can easily fit all of them onto a floppy disk. If you have a CD burner, even better: you'll need to move additional data, too. You can also always just email data to yourself. Small files can still be saved this way even if you have dial up, but of course, broadband makes this easier (though ISPs have upload limits).
You'd also want to save C:\Windows\Favorites.
There's lots more that needs backup, too -- but I'll save all that crap for now. If you aren't going to be moving data around, no use typing instructions. But by all means -- if you get a new PC, transfer the Cookies and Favorites. This will eliminate having to remember passwords and names associated with every single site.
And while odds are good that you will never need half or more of the cookies that you have on your system now, they are so tiny and inconsequential that just moving them all at once is the easiest thing to do. Sifting through each file, cookie by cookie, isn't worth the time or effort. Just copy the whole folder and be done with it.
Now, here's a FRIENDLY little lecture with some advice you need to know whether you get a new PC or not...
For the most part, there is no such thing as a free lunch. The good folks at AVG and Ad Aware and SpyBot -- exceptions to that rule. Their software IS free and contains no hidden gimmicks. Established and reputable websites like CFS -- they would never fuck with someone's system. Pop up ads are a necessarily evil that pays the bills -- but CFS, for example, would never force members to install bullshit spyware to access the site.
When you get all those messages popping up as you surf the web, asking if you want to install "Suckfucking Software Wallpaper Changer FREE FREE FREE" or some such bullshit -- select "NO", every single time. If you ever happen to see the option for "NO, FUCK YOU, FUCK YOUR MOTHER AND FUCK THE HORSE YOU RODE IN ON" -- click that!
Unless you KNOW you are a trusted site -- do not allow for anything to install on demand. You can force Windows to reject installs automatically using Internet Options (from the TOOLS menu on Internet Explorer or from Control Panel). Click the ADVANCED tab, scroll down to the BROWSING section, remove the check marks from INSTALL ON DEMAND (two entries).
I'd save this for a last resort, though. Install on demand can be useful in many cases and seems like an extreme measure to take, at least to me. Just manually reject ANY and ALL suspicious requests to install something on your PC.
And, um... porn sites will try to pull this crap quite often. Hmmm... just WHERE are you surfing, young man? Do I have to install Net Nanny for you?
Also, do not ever download anything you get in email if you don't know who sent it.
What you have on your PC is a Trojan horse, not "officially" a virus, but not a good thing, either. Viruses are hidden more easily in email attachments if people have accepted the Windows default settings to HIDE FILE EXTENSIONS FOR REGISTERED FILE TYPES.
I recommend you change this setting, if you haven't done so already. Just look at any JPG image on your system (or any file at all). If you can the .JPG extension, you are good to go. If you cannot, do this:
Select and highlight any file. Click the VIEW menu of the folder you are looking at. Select FOLDER OPTIONS, then select the VIEW tab. Remove the check mark from HIDE FILE EXTENSION FOR KNOWN FILE TYPES. Apply, OK.
Now you will ALWAYS see the file extensions. No one can trick you into running an EXE or a VBS by adding multiple extensions to it.
Finally, when running Ad Aware, the vast number of entries you'll see if you've never run it before can be worrisome at first. Don't panic: they are not ALL entirely malicious, and they are not all individual items seething within your PC. Many entries belong to just ONE little spy program, etc. You need to CHECK OFF all the found items in the resulting window and then click NEXT to remove them. This is annoying, but you'll only be presented with this massive list the first time. If you run Ad Aware regularly, very few new entries will appear and you'll have less to check off.
Now, if you DO have a new system that is running XP... Damn, man! I'll drive up there and rescue that poor baby! But if you have a system running Windows 98... fuck that.
Lastly, for real this time... It is NOT going to pose a problem if you were to get a new system and have someone (or even yourself) pop in the old hard drive and make it a slave to your new one (it's even a little kinky). The slave drive would NOT be a SYSTEM drive; it would not boot your PC. You can install it, transfer your data over in no time at all, then simply remove it again. The Windows folder it contains and any junk that is on there will just BE THERE: it won't be able to function (more or less -- that's the easy explanation for Luddites). You can just yank it out later, or format the sucker and have blank storage, easy as pie. Though with the size of newer hard drives, you probably won't need that storage space anyway.
Computer illiterate or not, what you are asking is all actually EASY stuff. It sounds like your buddy can help you out -- let him. Trust him on this. It's simple shit. I'd do it for you myself, but it wouldn't be worth the cost you'd have to pay me for gas money to get there! I'd also want you to hook me up with a good cocksucker, and then things just get more complicated, so...
Good luck!