I am a UK citizen. I have been rejected twice a year ago for an F1 visa under 214b due to a previous overstay. I am now enrolled at the university in the UK. I want to apply for a B2 visa to attend my sister's graduation. Will my university enrollment show enough ties? What are my chances of getting a B2 visa?
Yes you can however your chances are very slim. At this point it looks like you have adverse immigration history and this government is extra harsh on that. A year ago is relatively recent.
I would wait until you're working and have established strong ties to your place of residence before applying. Personally I wouldn't waste my application fee and have three refusals in a row.
Reference: Several somewhat similar cases on Travel.Stackexchange, immigration news etc.