Flash,sound,administrator rights +++problems

I have an HP Pavillion dv9000 laptop running xp media edition. I just got it back from Best Buy, where they replaced the screen, frame and plastic piece on cd drive.
Before taking it in, I appeared to have gotten the xp 2008 virus. It was impossible to delete, but now that I have the laptop back, it appears to be gone.

Also gone upon return is the sound on flash videos, though itunes and normal system sounds work. Somewhere, I got the idea that I should try uninstalling the flash viewer and re-installing it. Now it will not re-install. I've removed/uninstalled it with the uninstaller tool countless times and "reinstalled", but with no success.

Unfortunately, I've been going in circles I can't recall the order, but here's the problems I'm having:
*Flash installs in Firefox, but not windows(video, but still no sound). I installed Explorer 8 beta hoping something missing would be supplied-nothing changed.
*When I click on Tools>Internet Options, I get a "restrictions" error message telling me that restrictions on this computer prevent me from completing the operation and to consult the administrator (who is ME) I've been all over the "users" panel & there is no one else there. The "guest" is disabled.
*I'm unable to run "Microsoft Update" It asks me to download an active x control, but the pop-up bar does not appear with the option to OK the download.
*In addition, I always get these when booting up-the first, then the next: http://elisetimpe.com/Error.htm This, I believe, has to do with an update I downloaded for Ulead Videostudio. Though I've uninstalled and re-installed the program, the errors persist.

Does it sound like symptoms of one problem, or do I have several problems?
I use CCleaner regularly. I ran a full scan with the Corporate antivirus my company installed & it found and deleted several instances of trojan.dropper and trojan.bledso(sp?)

Thank you for any help you can give me.