Disk Cleanup Questions

I regularly use Disk Cleanup, as you should, to help clean some of the 'junk' out of my system and free up space. However, there are a couple things listed here I do not understand and am not sure I should 'mess with'. Let me say first that I have used up 20gb of my hard drive. I know not much, but I just recently did a new install. In Disk Cleanup I am comfortable deleting everything, but for two areas. They are:

1) System queued Windows Error Reporting Files: 988mb

2) TWO listings for: Per user archived Windows Error Reporting Files: 78.3gb each. That's GIGAbytes, not megabytes!

I am wondering if I can safely delete #1. I think I can. But I don't see how I can delete #2. In the first place, I have only 'used up' 20 gb on my hard drive, so what is this anyway?? I'd like a definition of each and the green light or not to delete the files in each one. Thanks.