Your admin could have chosen to encrypt some, or all drives - without knowing what version of EEPC you're using though it's hard to tell.
As for Dell Diagnostics, you don't say whether the problem is apparent only while trying to run that app, or if this is now a permanent state?
What's the situation when you boot the machine now?
I'm at release 6.1 to my recollection. The error message at boot now is as follows -
Windows failed to restart. A recent hardware or software change might be the cause. To fix the problem:
1. Insert your Windows installation disc and restart your computer.
2. Choose your language settings, and then click "Next".
3. Click "Repair your computer"
If you do not have this disk, contact your system administrator or computer manufacturer for assistance.
Info: The boot selection failed because a required device is inaccessible.
I have the installation CD but I'm stuck in this loop, as in the Boot Manager cannot read the drive.
What i do is decrpt 1st repair and endcrpt back btw it is hell alot of time wasted.
I usually do that especially boot record got problem with it.
Do take an effort to check all the OS & hardware running fine after decrypt and backup the files. sometime it is hard disk faulty then need to replace it.