Hi
When I turn on my p.c. it starts to load up then half way through loading xp a error message comes up saying issas.exe.systemerror. Also "an invalid parameter was passed to a service or function"is mentioned.and when I click OK on this box the p.c resets itself and does it again.I know this question has been asked but my PC won't start up in safe mode and even when I use my original windows cd, the whole thing just starts from over AGAIN.I'm going crazy.Is formatting even going to help

Thanks

Yes, formatting would help. If you decide to format, make sure you have the windows CD and the drivers that came with the computer, or the restore disks that came with it.

When exactly does it say that message? While the Windows XP screen is loading, with the little bar at the bottom (before you log in), on the welcome screen (while you log in) or after you log in (after the windows startup sound)?

Well, it sounds like your computer has been infected with the issass back door trojan. You can go into your system folder and remove the file from the command line but I can't guarantee that that would work. If you're having this kind of trouble the issas has already corrupted your registry. Without going through the registry and removing all the entries for the issas it'll just keep reinstalling itself. And since you're having boot troubles that means removing the drive and hooking it up to another computer externally. Even then you'd need the right utilities to bypass all the windows user permissions. It's a real pain in the butt.

Reformatting your computer MAY help but it may not. The problem with these trojan viruses is that they often embed themselves in the boot partition on the hard drive. Reformatting doesn't actually destroy the boot partition. So it may reinstall itself when you reinstall the operating system.

What I would suggest is using Darik's Boot and Nuke. This utility will overwrite the entire hard disk with zeros. It's the only way to truly destroy the data. Then reinstall XP.

Darik's Boot and Nuke (Hard Drive Disk Wipe)

Be warned... DBaN truly destroys the data on the disk so if there is anything on there that you want or need I would suggest taking the drive to a professional and have them back up any important data.

Hope this helps. :)

Instead of formatting, you could do this as well:

- Shut down your computer.

- Pull out the power cable for 30sec

- Replug the power cable and restart your computer in save mode (you need to press F6 when your computer is booting, right before the Windows loading screen)

- Go to Dos promt or Start > run type regedit

- Search for and issas (watch out there is a file named lssas.exe (with a "L")

- Remove the "string" named and issas.

- Close regedit

- Go to the system32 folder and search files for files named issas.exe look and the date and remove this file and all the files created on the same time and date in that folder.