Can I demand a refund?

Many car sales are "as is". See https://www.atg.wa.gov/buying-car. Continuing to try to negotiate a deal may be your best bet.

Once a judge issues a warrant, it remains in effect until quashed. Taking a proactive approach to clear the warrant is your best bet. If you wait...

H1b immigration issue?

See https://www.uscis.gov/news/news-releases/uscis-publishes-final-rule-certain-employment-based-immigrant-and-nonimmigrant-visa-programs

Your statement describes circumstances where a lawsuit for breach of contract may be viable.

Selling canvas wall art pictures online

The copyright laws do have some surprisingly serious penalties for infringement. https://www.copyright.gov/title17/

Is there recourse for negligent Microsoft customer support?

It seems unlikely that litigation based upon the circumstances you describe would be worthwhile.

Can someone sue a partner who back out in their agreement ?

Your statement and questions are somewhat vague. Courts can indeed hear cases alleging breach of contract or dissolution of partnerships.

I'm 16 and my girlfriend is going onto 15 is it legal to have sex?

See the following...

Can cps take my child away for legal marijuana consumption ?

The concern of CPS is to protect the health, safety, and well being of children. See https://www.dcyf.wa.gov/services/child-welfare-system/cps

"RCW 64.06.030 Delivery of disclosure statement—Buyer's options—Time frame. Unless the buyer has expressly waived the right to receive the...