|Firstly do not delete any individual files or folders unless you are quite certain what they are and/or they are personal files that you put in. We see many machines here which have been wrecked that way.|
For you to be as low as 1% free then there must be some big stuff on the machine or you have a small drive. Take a look in Control Panel > Add-Remove and see if there is any program there that you no longer use.
Look around for video files that you don't need because those are usually quite big.
I would also run an anti-virus and anti-malware scan.
Ms Hulot's boat