How do I calculate the collector current of this circuit with a bipolar junction transistor?
Step 1
Start out using the editor available to you, like this:



simulate this circuit &ndash; Schematic created using CircuitLab
Note that I've marked various nodes with names to allow better communication. The transistor is attached to three of the four important nodes, so I've just named them according to the associated BJT pin. The fourth node is the resistor divider voltage for \$R_1\$ and \$R_2\$ and since I'll use Thevenin for that, I called it \$V_\text{TH}\$. (The remaining nodes are obviously just ground and the power supply voltage rail.)
So that's the first thing to do. Get things named and lay out the schematic in some clean fashion. Each of us has to work out what works better, in that respect. But you might benefit from reading my discussion on how to draw schematics.
Step 2
Pick the low-hanging fruit available for simplifying the schematic. A very obvious step is shown below, which Thevenizes \$R_1\$ and \$R_2\$. I've also removed \$C_\text{BOOT}\$ because it doesn't contribute to the DC operating point for the BJT.



simulate this circuit
I think you can see that this is starting to look a lot easier to solve.
Summary
Are you able to take it from here? Or is this still too complex for your current state of knowledge?