Computer Crash Need a little help

I need a little computer advice. I have a dell 2400 that is seven years old, but was running perfectly until the other day. My wife wanted some store coupons, so I downloaded a program to get them, and my computer went to a white screen.

I rebooted, and all seemed ok. I left it running, and the next morning I had a blue screen, with a message that said something like"my computer had been stopped to prevent further damage. I could not get into safe mode, or do anything, so I gave it to a friend who is pretty good with this stuff.

He said I had a Trojan, and two viruses, and he had to overwrite my windows xp program, but I did not lose any of my files, which made me happy. Everything seems to be ok now, except for one thing.

Windows explorer will not work. When I try to use it, it will launch the browser, and then a message comes up saying there was a problem, and asks if I would like to notify Microsoft.

I have tried everything I know of. It is IE8. I was going to delete it, and download it again, but I was told it is intergrated into the windows program, and that won't work. Is that true.

I use firefox for almost everything, but I make a lot of niche websites, and I need explorer, to see how the sites look in that browser.

I know I can delete everything on my hard drive, and reload the operating system, but I am trying to save all the programs I have collected over the years. I have everything backed up, but there are some things you just can't back up.

I ran spybot, and it did not find anything.

Any suggestions would be appreciated.

Thanks Glenn