[NAME] is right about cleaning. It was a mistake to boot it before cleaning it. You need to completely disassemble the computer, remove virtually everything and carefully, gently, clean it with 99% alcohol. Don't use regular rubbing alcohol which is only 70% alcohol, because the other 30% is water. You need 99% alcohol. Use Q-tips or lint-free cloth like microfiber cloth, dip in alcohol and clean off residue from the spill. If liquid appeared to get onto CPU or GPU area, I would remove the heat sink and clean everything. After, you will need to apply fresh thermal compound. I would also replace the CMOS battery (coin-cell battery). Follow the disassembly and reassembly steps in Dell's Service Manual.Look on YouTube for videos showing disassembly of your model. But, be cautious with them, as some use steps or methods that are not appropriate. Use the videos to add to your understanding of what to do, but follow the steps in Dell's manual. Go slowly, keep organized, take photos and label locations and screws. I use a chocolate box with numbered compartments for screws, and I write down what part of the computer each number corresponds to. I also place small pieces of painter's tape on parts of the case and board, on which I write the number corresponding to the number of the screw compartment in the chocolate box. Whenever touching components or working inside a computer, wear a grounded wrist strap, also called anti-static wrist strap, ESD wrist strap, or ground bracelet. It's a cheap and sensible precaution. Rest the laptop on an anti-static mat or at least a reasonable alternative such as corrugated cardboard. When you're ready to try booting, if it appears that liquid got onto the battery or contacts, I would be inclined not to reconnect the battery and to boot with only AC power. If everything works, you can consider whether to try the battery. I recently refurbished an XPS that I salvaged from a recycling bin. One of its issues was that it obviously had a liquid spill inside it. I took almost everything apart to thoroughly clean it. Here are photos, though I had already put some components back before I took the photos.Disassembled XPS 15 L502x with photos. I salvaged and repaired it. - Dell Community Good luck!
In 2021 I accidently spilt a glass of wine on my laptop (on the keyboard). I immediately disconnected it, dried and turned upside down, but it stopped working. As the warranty had already expired, I took the laptop to a repair shop. They tried to clean it, but it didn't help. At this point they said they would propose replacing some parts, but it was in the middle of the pandemics and spare parts were not available for this model. I went to another repair shop to double check and they said the same thing: no spare parts. They suggested I should contact the Dell support, as maybe they would have spare parts available. I followed this suggestion and sent the laptop to the Dell support. After a few weeks they came back with the diagnosis that basically every part of the laptop (including the back cover!!!) had to be replaced because there were traces of liquid everywhere. These were the parts they wanted to replace: 6Y7DJ KYBD,82,US-INTL,M17NCC-UB 739-5683378KKT ASSY,PWA,PB,W/FPR,BLK,9370 891-10768C2T28 ASSY,SPKR,NBK,XPS,9370 739-56836G8VCF BTRY,PRI,52WHR,4C,LITH,SMP 739-56828MTDC8 ASSY,LCD,HUD,FHD,NT,SLVR,9370 739-56821RRKWP PAD,THRM,GRAPHITE,KB,XPS,9370 891-10768WHVT0 ASSY,PLMRST,82,BLK,9370 739-56836X3DF2 ASSY,CVR,BTM,SLIVER,9370 739-56836XNRD5 ASSY,PWA,NBK,I7-8550,8G,T,9370 739-56820 The total cost exceeded a price of a new laptop, so I passed on the offer. I put the laptop away and forgot about it. Fast forward to last week (January 2023), I was cleaning up, came across the laptop and decided to give it a try. To my surprise it booted. I was able to log in, all my data was there. It was charging, the display worked, the keyboard was working funny (as if it was sticky) but it was functional, I was able to connect a monitor, a mouse, a keyboard, I was able to connect to wifi. I was occasionally using it for the next couple of days. Unfortunately after about a week the laptop stopped working again. I can't boot it, the screen is black. Anybody has any idea what the problem could be?  
Dell XPS 13 9370 won't boot (black screen)