Windows won't start uxtheme.dll issue

hey peeps... i have an acer aspire 5920G with Vista and it will not start when it logs on i get the message:

winlogon.exe - Bad Image

C:\Windows\system32\uxtheme.dll is either not designed to run on windows or it contains an error. Try installing the program again using the original installation media or contact your system administrator or the software vendor for support.

when i click ok it says

Application error

The instruction at 0x7562a149 referenced memory at 0x00000000. The memory could not be read.

Click OK to terminate the program.

and when i do its just black and the screen turns off with the computer doing processes.

i have tried a restore point but it says there are errors witht he memory and scans the memory saying its fixed but when i go to restore it still says there are errors.

i have took out the hard drive and looked though it as an external drive and i can access it no problem.

complete system restore wont work either as it says there are errors there no no joy.

i have been able to access the admin account in cmd and run sfc/scannow and restarted but still the same problem.

i cant boot safemode and now i cant access the cmd in safe mode someone help i cant access anything on the system at all.

thanks
 
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