Hello iNexxFear
Try to run Oblivion in Administrative mode and you said your currently OS is
Vista Home Premium so it's nice but try get some of the best edition in vista
alike Vista Ultimate (
TORRENTS | TO | Your BitTorrent Search ) and
Oblivion:Tweaking - UESPWiki , Visit this site and follow their
Method for Oblivion
2nd thing is don't forget to installed DirectX 10 on your OS
and Defragment your Pc again Run oblivion
If it doesn't work then your system may be want some of the upgrade
to
Windows Vista Ultimate
2GB of DDR2 Ram
256MB of Nvidia Geforce 7 Series VGA PCI-Express 16X
ATI 256MB Radeon X1300,X1600 VGA PCI-e 16X
Speed is too slow and it must be upgrade to 2.8GHz
Virtual Memory Upgrade to 3GB
Close all programs While oblivion running
and My Advice is Oblivion is too much for running in Windows XP and DirectX
9.0c having Windows Xp SE2 (
TORRENTS | TO | Your BitTorrent Search ) why do you play Oblivion in Windows VISTA?
Get Oldblivion (
Oldblivion) if you have this problem in Windows XP