Laptop hangs often and is very slow, what can I do?

I have an Acer Aspire 3 laptop with 8 GB RAM and 512 GB SSD. I've had the device since about last December and it's extremely slow now. I have already reset the laptop to factory settings several times, but it has not worked. I have already tried to empty the RAM memory.

I have to send a lot of mails and the mail program on the laptop is just crazy. It never sends the mails and does not display them anywhere (neither in drafts nor in sent or anywhere else). Sometimes they are sent all at once the next day when I turn the laptop on again. That's why I've often sent emails twice. In addition, it often changes the mails to such a strange font format where there's a space after each letter (I once inserted a picture how it changed that)

What can I do to make the laptop run smoothly again?

I can't afford to go to a repair service or anything at the moment…

Thank you for your answers.

A cleaning is probably due!

You can do this yourself or by a professional. The costs for this should be limited (if not free).

To your mail problem:

Which mail program do you use? More information would be good.

I use the pre-installed Windows mail program, my account is with gmail