Yeah, I always worry about messing my system up. BUT ... I just recently found a DYNAMITE freeware program that completely protects me from screwups. Rollback RX. I love this thing.
After an initial 'snapshot' of your total C drive (takes about 90 seconds), you can take other snapshots at will. And it truly takes only 10-12 seconds, and the files are smallish (1GB maybe). To restore, just open the little Rollback RX program (in Windows), choose which snapshot you'd like to revert to, and it forces a reboot. The reboot takes a whopping 20 seconds longer than a normal boot, and voila! A perfect restore.
The only issue I see is that Rollback stores its snapshots on the C drive and that can't be changed. So just in case of a total disk failure, I keep a few Macrium Reflect images on a removable external drive. That's also a totally free program.
Before I install a program I take a snapshot. Just today, I did that, installed a freeware PDF reader that messed up my system, and Rollback RX restored perfectly to just before I did that install. And I'll take a snapshot before I update Windowblinds again - I didn't see anything that looked 'damaging' in the backup Zip file I made, but ... what do I know?