Hi Logan -
Use
Partition Wizard bootable CD which gives more options and rescue ability.
If Windows 7 will still not offer Modify>Set Active, try deleting Acer partition first.
Then rightclick Windows 7>Modify>Set to Active, OK.
Now rightclick Windows 7>Resize>drag left grey border all the way to the left over deleted Acer partition space, OK.
If it all looks correct, then Apply steps.
Windows 7 will not boot now. Instead boot into Windows 7 DVD, select Repair on second screen, click through to Recovery Tools list to run Startup Repair up to 3 separate times with reboots to write MBR to Windows 7.
As resizing operations can fail, make a Windows 7 backup image stored externally first so you can start over if necessary, and always back up your files.