Before I saw this I ran the Chkdsk app, and the problem appears to have gone. Thanks for your help, bit I'll leave it a couple of days before I check this thread of as solved.
Computer type PC/Desktop System Manufacturer/Model Number Compaq SR5710F [Case only] OS Windows 7 Ultimate x64 CPU AMD FX 8150 [16 Megs total Cache] Motherboard Asus M5A88-M Memory 16 Gigs [1 Gig for Shared Vid mem] Graphics Card Integrated ATI Radeon HD 4250 GPU Sound Card ALC892 8-Channel High Def Audio Monitor(s) Displays VGA main, HDMI to TV Screen Resolution VGA Screen: 1440 x 900 TV Screen: 1920 x 1080
Keyboard Wireless Mouse Wireless PSU 850 Watt Case Compaq SR5710F Cooling Default Hard Drives 120 Gig SSD 80-Gig secondary [VMs]
~5TB on server. [My Docs, Photos, Music, Desktop folders are on the server] Internet Speed Slow-ish Broadband Antivirus Microsoft Security Essentials Browser IE Other Info Blue-Ray DL drive Z:\
Server: 2Ghz Single core, with about 5TB on it. WinServ2003Enterprise
MacBook: 2Ghz Core2Duo, 2Gigs, Snow 160Gigs
Toshiba Lap: 2.4Ghz, Single Core, Win7
Acer AspireOne: 1.6Ghz, Dual-Core, 1 Gig, XP Home
HP Lap: 1.8[?] Quad-Core, Win7
4 Android Devices
2 iPod Touch
The problem appears to have fixed, thanks for your help. I'll leave this unsolved for a couple more days just to make sure the problems are fixed and then I'll make a final judgement