So hang onto the windows.old folder until the day comes when you can say for certain that you have everything you need from Vista then run Disk Cleanup and delete it.
Now install your Important and Optional Windows Updates. It occurs to me that the Acer Upgrade disk does not have SP1 so you'll have to wait until Updates gives it up and install it in a day or so. Had you told me earlier that you had the Acer Kit I would have steered you to the latest official installer with SP1 in Clean Reinstall - Factory OEM Windows 7
to save hours of updating.
Read through that tutorial to pick up some optimization tips, the tools and methods we have learned here to get and keep a perfect install.
If you only chose to install to C and didn't delete all partitions before install then you'll still have the Vista Recovery partition and another useless Acer tools partition which you can later delete and resize Windows 7 into it for more space: Partition Wizard CD Resize Partition - Video Help.