Speccy url worked ok
MSE needs to be fully uninstalled and not just disabled as the potential is still there for it to conflict.
Bit of a recap;
From my reply #2
The DELL 450 Workstation originally shipped with XP meaning that the Dell Utility Partition must have been reinstalled at some point, is that correct.
From your reply #7
I did, a few days ago, reload the Windows 7 OS
Your screenshots in reply #5 and Speccy only show the one partition (C:) which is where Windows 7 is, there is no evidence of a Dell Utility Partition, can I ask how Windows 7 was reinstalled, was it from a Windows 7 disk or a back up image that you created yourself.
JAFYI: I have encountered such behaviour before and also with a Dell, after having to replace a faulty HDD the computer would only boot after F2 had been pressed, this was either because the Dell BIOS did not recognise the new HDD or because the original XP OS had been replaced with Windows 8, your C: partition is labelled as XP which may suggest that a Custom Install of Windows 7 was done and the without reformatting your drive or partition option was selected, if this was the case there should be a Windows.old folder, to check if there is;