I didn't download media center, i bought it from a website (digital-sunrise.co.uk).
for more info on the stop error message, here it is:
A problem has been detected and windows has been shut down to prevent damage to your computer
A thread tried to release a resource it didn’t own.
If this is the first time this you have seen this stop error screen, restart computer. If this appears again, follow these steps:
Check to make sure any new hardware or software is properly installed.
If this is a new installation, ask you hardware of software manufacturer for any windows updates you might need
If problems continue, disable or remove any newly installed hardware or software, disable BIOS memory options such as caching and shadowing.
If you need to use safe mode to remove r disable components, restart your computer, press F8 to select advanced start-up options, then select safe mode.
Technical Information:
***STOP 0x000000E3 (0x855E93EO, 0x805591A0, 0x85342328, 0x00000003)
Beginning dump of physical memory
Physical memory dump complete
Contact you system administrator or technical support group for further assistance