Can you give us an example of the errors you are receiving?
Can you tell me how many partitions you have on your machine and is vista the only operating ystem you have installed?
Do you have a full version Vista disk for your machine?
What I woudl suggest first would beto use atool built into Windows calledthe System File Check, What this does is compare the files on your machine against the originals on the disk and replaces any that are damaged.
Can you click the Start button then from the Start Menu, Click All programs followed by Accessories and right Click on the Command Prompt option
From the drop down menu that appears, Click on the Run as administrator option then in the Command Prompt window, type: sfc /scannow and then press Enter
Then just let the scan runand reboot when finished and let me know what happens.
Usually I work from 6pm onwards, however this morning I was following up with some other clients, However if you wish to contine I will be available all night.
Can you next run a chkdsk command and then defrag the drive.
To run chkdsk can you open the command prompt with administrative privileges by typing cmd in the search box in the Start Menu and right-click cmd.exe in the search results and then select Run as Administrator. and then from the dos prompt type chkdsk then a space followed by /r so "chkdsk /r" without the quotes and hit enter.
After the chkdsk has run can you reboot and then click start and type defrag, then launch and run the tool.
Once that is finished let me know how your logs look.
Have your error logs cleared up since the defrag?
How many drives do you have in this machine?
Are you using an USB drives or using a CD or DVD when this happens?