Plz help with Windows Mail

Hi, im new to windows 7 and im lost. my comp was running fine for the first week that i had it but not is gone berserk. I dont know what happened, but my windows mail that I set up is now only showing mail that I had left on my email client servers and didnt download to my machine. I have about 40 or so message that just disappeared and have no idea were they went. some are not that important but I have some messages in there that I really need to get back. I tried to do a system restore to see if that would help. I had about 3 or 4 system restore points that some how made themselves and now they do not show up anymore. I tried to make a system restore point myself but that doesn't seem to work either the system seems to say that I have a 0x8000ffff catastrophic failure. I have no idea how to trouble shoot that. I thought that my external hard drive might have something to do with it. My new machine insisted that I reformat, but I dont want to b/c I will loose all my data, which may have given me a virus from my old machine that tweaked out on me. I tried downloading several anti-virus programs from Cnet but each time the download was stopped mid-way and told me that an error occurred. When I clicked ok and tried to continue I received a message that says "not enough space available to process this command" but my hard drive is brand new and shows that I have over 250GB left. I dont understand this. Thought it could be a compatibility error but still nothing. I tried searching online for help for my problems and something was said about shadow volume being turned off or stopped. i switched that to auto and started it. Still cannot do system restore to previous point in time, because the points don't show up. I believe that the comp may have tried to delete them automatically thinking that there wasn't enough available space left on the machine. i don't know what to do or how to fix these problems. I'm at a loss here and I have a week old machine. please help!!!! Thank you.

Hi, thanks for the quick response. I was able to download the malwarebytes, from Cnet successfully. I find this weird because avast, avira, and especially AVG9-free gave me problems when i tried to download them. I did a full system scan, it took 38 min. there result was there was no malicious hardware found.

Malwarebytes' Anti-Malware 1.44
Database version: 3921
Windows 6.1.7600
Internet Explorer 8.0.7600.16385

3/27/2010 9:33:04 PM
mbam-log-2010-03-27 (21-33-04).txt

Scan type: Full Scan (C:\|D:\|E:\|)
Objects scanned: 266155
Time elapsed: 38 minute(s), 33 second(s)

Memory Processes Infected: 0
Memory Modules Infected: 0
Registry Keys Infected: 0
Registry Values Infected: 0
Registry Data Items Infected: 0
Folders Infected: 0
Files Infected: 0

Memory Processes Infected:
(No malicious items detected)

Memory Modules Infected:
(No malicious items detected)

Registry Keys Infected:
(No malicious items detected)

Registry Values Infected:
(No malicious items detected)

Registry Data Items Infected:
(No malicious items detected)

Folders Infected:
(No malicious items detected)

Files Infected:
(No malicious items detected)


Now, is there another possiblity that would have caused my system to act like this (services, device manager or something of the sort). I dont know what to do.

I have also managed to download iobit 360 security, and I have done a full system scan. No viruses show up.