A couple of days ago I decided to put a password on my user account. I am the only user on the computer, and I have administrator status. When I added the password and rebooted, the welcome screen stayed longer than usual, and then I was shown my desktop picture but no start menu bar, no icons, nothing. I was able to access Task Manager, and went poking around in dos.
We saw that "explorer.exe" was missing, so I tried FixO (suggested by another thread on this site). Two of the files in that zip appeared, but the third (restore.reg) was hidden, and I couldn't figure out how to unhide it. Eventually, I booted from the Windows XP disc, and that made my start menu bar and icons come back. I tried to do a Windows Update, but was prompted to update my windows update software. When I tried to do that, I got various error messages (a couple of different numbers). I updated Avast and ran a thorough scan. It found 5 trojans in 5 different places. I moved them all to chest and then deleted them. I ran another scan, and it found nothing.
I noticed that I was getting no sound from my speakers (back when I had no start menu bar or icons, I still got the Windows Welcome Music everytime I rebooted, but now that was gone). I was just getting the occasional beep from the CPU. So I went into Control Panel. The audio settings buttons and menus were all greyed out. I reinstalled the monitor driver (speakers are on the monitor). No change. I googled that problem and saw that maybe my account didn't have permission to change those settings. Checked my user account, checked regedit, and I'm still an administrator and all the right administrator permissions were checked.
Today when I got home from work, I turned on the computer to find that the internet didn't work. No available wireless connections, a network cable has been disconnected, etc. Same as with speakers -- when I brought up the settings windows, everything was greyed out, and there were no available wireless networks. I tried to print off some work I had to do at home, in case something else decided to go, but the printer wouldn't print. No error messages, though; it just didn't respond. The printer icon stayed in the system tray (it's still there, 3 hours later).
I have no idea what could be going on. I hope someone can help me!