Hi, i recently got a new mic, its a ATR1300 Audio Technica and i plan to record my guitar and vocals onto my laptop. I don’t have any audio interface so how i connect my mic to my laptop is by buying a adapter which connects the mic plug to the mic input on my laptop. I launch Audacity and tried to record and everything seems fine. I remove the background noise by using Noise Removal and it’s perfect. However a few hours later, when i tried to record again there is this constant high pitch sound in the background and when i use the Noise Removal my voice sounded like a robot and the high pitch sound is still there. When i tried on my sister laptop everything is fine. Only on my laptop there is a problem. please help me Thanks 
Most PC laptops have poor quality mic inputs. For reasonable quality audio recording it is usually necessary to upgrade the audio interface. The most popular way of doing that for a laptop is to purchase a USB audio interface. There is a huge range of USB audio interfaces available. Many (but not all) support plugging in a microphone, but usually this is via a 3 pin XLR connector:
Some USB interfaces support mini-jack or 1/4" jack microphones, but usually these are low quality. XLR is the way to go for good microphone recording.
There are other approaches, such as buying a USB microphone (plugs directly into a USB port), or using a “line level” USB interface with a mixing desk and plugging the mic into the mixing desk. There are pros and cons to each approach. The main considerations tend to be “budget” and “what exactly you want to do”.
There is a very detailed topic about an Audacity user tackling this subject here: https://forum.audacityteam.org/t/non-usb-mic-for-classical-guitar-rec-findings-conclusions/13464/1
Thanks for the responds! I guess ill buy a usb audio interface than. 