My C drive is running out of space. How do I free it up?

My main drive is the C drive and it's being used up by programs installation etc.
I think I need to free it up in order to let my programs run smoothly.
And I have a lot of space in my D drive.

Is there a way to change my main drive to D instead without reformatting?

No. But it's possible to shrink the partition for your D: drive and then grow the partition for your C: drive assuming that they are both parts of a single larger disk that has been partitioned into 2 smaller disks. You can use free software such as those listed in this article to do it: 9 Free Disk Partition Software Tools (May 2017)

Goto C:\Windows\SoftwareDistribution\Download and delete everything in the folder. Reduce the space reserved for restore points to say 5% of Your SSD capacity. Reduce the amount of Virtual Memory to something like 1024/1024 or 2048/2048 (Yea, Bat got OCD) Follow the advice already given You about using D: for storage and/or get a larger SSD.

^ Thanks for the advice Bat 1. How do I go about doing the following:
I cannot amend the virtual space as it claims it has no enough space. Any other advice I can get?

I actually forgot I have opened a previous thread about this. Apologies, work has been too hectic and I haven't had a chance to fix this until recently when there's a prompt on this on my laptop.