I found myself in a similar situation a while back. Also an Acer, it kept giving me warnings about disk space nearly full. Cleaned up the drive etc - helped a bit, removed photos, videos etc, unwanted programs - helped a bit more but still, there was almost nothing left on this thing and still no room
Eventually I thought to look at how much capacity there was to begin with, it was like 10gb or something ridiculous, less than my bloody mobile phone
I think you've just found the perfect excuse to go shopping
ps buy a mac, you won't look back