Sorry but I agree with your conclusion. Backup everything. The best way to do this is to buy an external USB attached hard drive.
Download and install Macrium Reflect Free
Create a Macrium Rescue disc.
Backup the entire hard drive, MBR, Recovery Partition which is normally 4-5GB in size, definitely under 10GB and boot partition.
According to the Users Manual
, there is a Recovery Partition on the hard drive. You could try restoring that as follows:
Using Dell PC Restore by Symantec
Use Dell PC Restore by Symantec only as the last method to restore your operating system. PC
Restore restores your hard drive to the operating state it was in when you purchased the computer.
Any programs or files added since you received your computer —including data files—are
permanently deleted from the hard drive. Data files include documents, spreadsheets, e-mail
messages, digital photos, music files, and so on. If possible, back up all data before using PC
NOTICE: Using PC Restore permanently deletes all data on the hard drive and removes any applications or
drivers installed after you received your computer. If possible, back up the data before using PC Restore.
To use PC Restore:
1 Turn on the computer.
During the boot process, a blue bar with www.dell.com appears at the top of the screen.
2 Immediately upon seeing the blue bar, press <Ctrl><F11>.
If you do not press <Ctrl><F11> in time, le t the computer finish restarting, and then
restart the computer again.
NOTICE: If you do not want to proceed with PC Restore, click Reboot in the following step.
3 On the next screen that appears, click Restore.
4 On the next screen, click Confirm.
The restore process takes approximately 6–10 minutes to complete.
5 When prompted, click Finish to reboot the computer.
NOTE: Do not manually shut down the computer. Click Finish and let the computer completely reboot.
6 When prompted, click Ye s.
The computer restarts. Because the computer is restored to its original operating state, the
screens that appear, such as the End User License Agreement, are the same ones that
appeared the first time the computer was turned on.
7 Click Next.
The System Restore screen appears and the computer restarts.
8 After the computer restarts, click OK.
If that doesn't work and you don't have a Install or Recovery CD then you can try the following which I've done successfully several times.
Replace the old drive with a new one.
Boot the Macrium Rescue disc.
Restore the Recovery Partition and MBR. You can also try restoring the boot partition and see what happens. If all is well you're done. If not then use the Ctrl+F11 key at boot time to start the Symantec Recovery process and restore the system to factory new state.
Install Macrium Reflect Free again then you can browse the backup you made of the boot partition and restore your data.