cannot share printer on network

In trying to download some programs from online, the last one was Sygate Firewall from MG's, I am getting an error that reads, "Error 1335. The cabinet file 'Cabs.w1.cab' required for this installation is corrupt and cannot be used. This could indicate a network error, an error reading from the CD-ROM, or a problem with this package. Retry or Cancel."
I also cannot get my computer to connect with a shared printer on my home network, even with firewalls off, & printer marked to allow sharing. Keep getting errors that says printer is not online, etc...but this is NOT the case.

Also, upon attempting to download Belarc Advisor from MG's, I got an error that says "An I/O error occurred while installing a file. This is normally caused by bad installation media or a corrupt installation file. Abort or Retry."

I'm running WinXP-Home SP2, Gigabyte K8Triton NForce4SLI, AMD Athlon 64, Running 3-PCs through a Belkin router & cable modem. This setup is fairly new for me, as I just built it...was working okay upon starting out. Problems didn't seem to start until after I downloaded Microsoft Office '03 update.

Any help would be much appreciated ! Thanks!

 

I recommend you visit this thread and follow all the steps within.
Then, I would consider a visit to this thread and follow those steps too.

Doing so will ensure that you are free from malware, and establish a baseline upon which we can begin to troubleshoot your problem, if it still exists after these steps. The errors you're getting don't make any sense to me in the context that you've described. I bet these threads will help you.