I'm in the process of trying to launch a new start up company but also still working full time for another company. Is it ok to start having my personal paychecks directly deposited into my new business account ?? How can I use money from my personal checks for starting my business ?
Mixing personal and business funds as you described just makes it harder to deal with when problems arise (and they will). I recommend that any funds which may have tax consequences, like wages and dividends, should go into an account with the correct tax id/name. If there are any disputes, there is no need to bring in other aspects of your life.
As you have personal funds you can transfer funds over to your new business. Such investments are consider
capital investments toward the business.
Since you mentioned you are in the United States there a number of sources for guides/assistance for new businesses, the IRS has a Small Business and Self-Employed Tax Center, and the Small Business Administration are places to learn about what you need to do. If you need someone to talk to, look to see if there is a SCORE chapter near you.
NOTE: This site is for personal money matters so beyond this would be off-topic.
Don't do it. You need to start thinking of your company as a legal person separate from yourself. With its own SSN (EIN), its own bank accounts, its own checkbook. It never pays your cable bill, and you never pay its payables. It's like you are the trustee of your new baby company.
So keep having your paychecks deposited in your personal account. When you need to inject capital into the company, write a check to the company, deposit it in the company's account, and post it to the company's general ledger as "capitalization" (capital investment). You're gonna want that later.
The trouble is, when you just start forming a business, it's really hard to know all the stuff you're going to need later when you're bigger, incorporating, doing an IPO, going chapter 11 and trying to shield your personal assets, etc. etc.
For instance if someone is suing your business, they will try to "pierce the corporate veil" and go after your personal assets. One attack is saying you failed to capitalize enough. Records of your initial contributions prove that wrong and save your bacon.